Abstract
Trace metal elements commonly exist in drinking water. Excessive exposing on them may result in lots of health problems. This
paper mainly focuses on the accumulations of Cu2+, Cd2+, and Pb2+ in drinking water supply networks with amorphous Al(OH)3
formation. The effects of pH, water flow rate, and metal element contents were investigated at laboratory bench scale. It was
found that chemical adsorption mainly occurred at pH > 7.0. Suspended Al(OH)3 showed a strong adsorption capacity for Cu2+,
Cd2+, and Pb2+; 1.0 g Al(OH)3 could accumulate 43.0 mg of Cu2+, 30.0 mg of Cd2+, and 34.6 mg of Pb2+ at 15℃, respectively.
Thermodynamic calculation results indicated nearly all of the Cu2+ and Cd2+ were adsorbed at pH 6.5-8.5, chemical precipitation
did not occur in the presence of suspended Al(OH)3. Because of H+ inhibition, the adsorption of Cu2+, Cd2+, and Pb2+ would be
inhibited under acidic condition. Unlike suspended Al(OH)3, Al(OH)3 scale showed a much lower adsorption capacity for Cu2+,
Cd2+, and Pb2+, at approximately 0.4, 0.4, and 0.7 mg/g, respectively; and the variation of flow velocity and solution pH had
minor effects.